การผลิตถ่านชีวภาพจากกากกาแฟในปฏิกรณ์ไพโรไลซิส แบบเบดนิ่งที่มีลูกบอลโลหะช่วยกระจายความร้อน

Abstract

In this study, slow pyrolysis of spent coffee ground (SCG) in cylinder shape fixed bed reactor was investigated with the aim to develop the way increasing the heating rate of SCG in the bottom center of reactor. The small metal balls 8mm diameter were used as the thermal distributor within the final temperature 500°C, 50 ml/min of N2 gas flow, and holding time at 1 and 2 hrs. The results reveal that the heating rate of spent coffee ground in the bottom deep center of the reactor with small metal balls (SCG+MB) was increased. The properties of product biochar of two experiments at the same temperature 500°C between SGG holding time 2 hours and SCG+MB holding time 1 hour was not different. That was shown that the addition of metal balls affected the decomposition of coffee grounds. These results claim that the pyrolysis which having metal balls can improve the raising of heating rate of the pyrolysis. The addition of metal balls could reduce production time, this results in a reduction in electricity consumption by 35.11% and the cost of SCG+MB production was 1418 Baht per kilogram. The sensitivity analysis revealed that labor costs had the greatest effect on the cost of biochar production.